Method for forming a metal oxide film

• US 7,256,144 B2
• Filed: 03/24/2004
• Issued: 08/14/2007
• Est. Priority Date: 03/27/2003
• Status: Expired due to Fees

• Current Assignee: Longitude Licensing Limited (Vector Capital Corporation)
• Original Assignee: Elpida Memory Incorporated (Micron Technology, Inc.)
• Inventors: Koyanagi, Kenichi, Sakuma, Hiroshi
• Primary Examiner(s): Everhart; Caridad
• Application Number:
  US10/808,193
• Publication Number:
  US 20040192036A1
• Time in Patent Office: 1,238 Days
• Field of Search: 438/628, 438/240, 438/778, 438/785, 438/396, 438/680, 257/E21.01
• US Class Current: 438/785
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: H01L 21/02175 characterised by the metal H01L21/02197 takes precedence
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• CPC Class Codes: H01L 21/02181 the material containing hafnium, e.g. HfO2
• CPC Class Codes: H01L 21/02183 the material containing tantalum, e.g. Ta2O5
• CPC Class Codes: H01L 21/02186 the material containing titanium, e.g. TiO2
• CPC Class Codes: H01L 21/02189 the material containing zirconium, e.g. ZrO2
• CPC Class Codes: H01L 21/02194 the material containing more than one metal element
• CPC Class Codes: H01L 21/022 the layer being a laminate, i.e. composed of sublayers, e.g. stacks of alternating high-k metal oxides adhesion layers or buffer layers H01L21/02304, H01L21/02362
• CPC Class Codes: H01L 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/3141 Deposition using atomic layer deposition techniques [ALD]
• CPC Class Codes: H01L 21/31637 Deposition of Tantalum oxides, e.g. Ta2O5
• CPC Class Codes: H01L 28/84 being a rough surface, e.g. using hemispherical grains
• CPC Class Codes: H01L 28/90 having vertical extensions
• CPC Class Codes: H10B 12/033 the capacitor extending over the transistor

Abstract

A method for forming a capacitor insulation film includes the step of depositing a monoatomic film made of a metal by supplying a metal source including the metal and no oxygen, and depositing a metal oxide film including the metal by using a CVD technique. The method provides the metal oxide film having higher film properties with a higher throughput.

Claims

1. A method for forming a semiconductor device comprising the steps of:

depositing a monoatomic film including a metal on a base by using a metal source including a compound containing said metal and no oxygen;

depositing a metal oxide film including oxide of said metal on said monoatomic film by using a CVD technique; and

before said monoatomic film depositing step, the step of supplying oxidizing gas onto a surface of said base.

2. The method according to claim 1, wherein said oxidizing gas includes heated H₂O.

3. The method according to claim 1, wherein said oxidizing gas includes at least one gas selected from the group consisting O₂, active oxygen, ozone, and N₂O.

4. The method according claim 1, further comprising, before said monoatomic film depositing step, the step of supplying hydrofluoric acid onto a surface of said base.

5. The method according to claim 1, wherein said metal source includes at least one said compound selected from the group consisting of TaCl₅, TaF₅ and Ta(N(C₂H₅)₂)₃, and said metal oxide film is tantalum oxide.

6. The method according to claim 1, wherein said metal source includes Al(CH₃)₃, and said metal oxide is aluminum oxide.

7. The method according to claim 1, wherein said metal source includes TiC₄ or Ti(N(CH₃)₂)₄ and said metal oxide is titanium oxide.

8. The method according to claim 1, wherein said metal source includes at least one said compound selected from the group consisting of Hf(NCH₃)₂)₄, Hf(N(C₂H₅)(CH₃))₄ and Hf(C₂H₅)₂)₄, and said metal oxide is hafnium oxide.

9. The method according to claim 1, wherein said metal source includes at least one said compound selected from the group consisting of NbCl₅, NbF₅ and Nb(N(C₂H₅)₂)₃, and said metal oxide is niobium oxide.

10. The method according to claim 1, further comprising, between said monoatomic film depositing step and said metal oxide film depositing step, the step of supplying oxidizing gas onto a surface of said monoatomic film.

11. The method according to claim 1, wherein said base is either silicon substrate, polysilicon film, silicon nitride film or a metallic film.

12. The method according to claim 1, further comprising the step of forming a conductive film on said metal oxide film, wherein said steps are used for forming a capacitor including said base as a bottom electrode, said metal oxide film as a capacitor insulation film, and said conductive film as a top electrode.

13. A method for forming a semiconductor device comprising:

depositing a monoatomic film including a metal on a base in an oxygen-free environment; and

depositing a metal oxide film including an oxide of the metal on the monoatomic film using a CVD technique; and

before said monoatomic film depositing step, the step of supplying oxidizing gas onto a surface of said base.

14. The method of claim 13, wherein the semiconductor device is adapted to function as a capacitor.

15. The method of claim 13, wherein the depositing of the monoatomic film including the metal includes using a metal source including a compound containing the metal.

16. A semiconductor device formed by a method, the method comprising:

depositing a monoatomic film including a metal an a base in an oxygen-free environment; and

depositing a metal oxide film including an oxide of the metal on the monoatomic film using a CVD technique; and

before said monoatomic film depositing step, the step of supplying oxidizing gas onto a surface of said base.

17. The semiconductor device of claim 16, wherein the semiconductor device is adapted to function as a capacitor.

18. A method to form a semiconductor device comprising the steps of:

depositing a monoatomic seed layer containing a metal on a base by using a metal source including a compound containing said metal and no oxygen, said deposition done via an atomic layer deposition (ALD) technique; and

introducing an oxygen source to convert said monoatomic seed layer containing metal to a monoatomic seed layer containing a metal oxide and depositing a film of the same metal oxide on said monoatomic seed layer via a CVD technique; and

before said monoatomic seed layer depositing step, the step of supplying oxidizing gas onto a surface of said base.

19. The method of claim 18, wherein said metal source includes at least one said compound selected from the group consisting of TaCl₅, TaF₅ and Ta(N(C₂H₅)₂)₃, and said metal oxide film is tantalum oxide.

20. The method of claim 18, wherein said oxygen source is O₂ gas.

21. The method of claim 18, wherein said metal source includes at least one said compound selected from the group consisting of Hf(NCH₃)₂)₄, Hf(N(C₂H₅)(CH₃))₄ and Hf(C₂H₅)₂)₄, and said metal oxide is hafnium oxide.

22. The method of claim 18, wherein said metal source includes at least one said compound selected from the group consisting of NbCl₅, NbF₅ and Nb(N(C₂H₅)₂)₃, and said metal oxide is niobium oxide.

23. A method for forming a semiconductor device comprising the steps of:

forming a bottom electrode having thereon hemi-spherical grains;

forming a silicon nitride film on said bottom electrode by using a rapid thermal nitration technique;

forming a capacitor insulator film on said silicon nitride film; and

forming a top electrode on said capacitor insulator film, said capacitor insulator film forming step including;

providing oxidizing gas to bind oxygen atoms onto a surface of said silicon nitride film;

depositing a monoatomic film including a metal, by using an atomic layer deposition technique using a source gas including said metal, onto said silicon nitride film bound with said oxygen atoms; and

forming, subsequent to said depositing step, a metal oxide film including oxide of said metal on said monoatomic film by using a CVD technique.

24. A method for forming a semiconductor device comprising the steps of:

forming a bottom electrode having thereon hemi-spherical grains;

forming a silicon nitride film on said bottom electrode by using a rapid thermal nitration technique;

forming a capacitor insulator film on said silicon nitride film; and

forming a top electrode on said capacitor insulator film, said capacitor insulator film forming step including;

providing oxidizing gas to bind oxygen atoms onto a surface of said silicon nitride film;

depositing a monoatomic film including a metal by using an atomic layer deposition technique using a source gas including said metal, onto said silicon nitride film bound with said oxygen atoms;

oxidizing said monoatomic film to form a metal oxide film including said metal; and

depositing another metal oxide film including oxide of said metal onto said metal oxide film by using a CVD technique.